Date: June 4, 2015

1. PURPOSE / DESCRIPTION

• To set a standard procedure for wind tunnel simulation in ANSYS Fluent
• The procedure follows the wind tunnel simulation that was run for the NX Drone
• Useful resources:
  • Full course videos on ANSYS website for Fluent.
  • “Workshop 04: Airfoil” from ANSYS Fluent full course materials
  • “Workshop 08b: Vortex Shedding” from ANSYS Fluent full course materials
  • General Tips: http://www.computationalfluiddynamics.com.au/category/tips-and-tricks/
  • Viscosity Calculator: http://www.lmnoeng.com/Flow/GasViscosity.php
• If you have no experience with ANSYS, it is recommended that you go through the ETP for Learning ANSYS.

 

2. PROCEDURE

Getting Started

• If starting with a new project with a mesh, (if without mesh, refer to the DM and Meshing procedure)
  • Drag and drop a Fluid Flow (Fluent) system under Analysis Systems into the white space in Workbench.
  • Import the mesh by right clicking on the Mesh cell > Import Mesh File… > Browse
  • DCLK (double click) on the Setup cell, check Double Precision, and click OK in the following window to open Fluent.
• If starting from completion of the related DM and Meshing procedures, then simply DCLK on the Setup cell.

 

Setup

• General
  • Click on Report Quality (Confirm that the values that appear are not close to the extremes that Fluent describes. Minimum orthogonal quality should be above .05)
  • Click on Check
• Models
  • DCLK (double click) on Viscous
    • Model = k-omega (2 eqn)
    • k-omega Model = SST
    • Check Low Re Correction
  • Materials
    • DCLK on air under Fluid
      • Density (kg/m3) = 1.1845 (This is for 25 C; use appropriate value found for certain temperature. Also, we can assume constant density because of the relatively low air velocity.)
      • Viscosity (kg/m-s) = 1.8444e-05 (this is for 25 C; use appropriate value found for certain temperature.)
      • Click Change/Create
    • Cell Zone Conditions
      • Click on the cell zone (there should only be one).
      • Confirm that Type is set to fluid.
    • Boundary Conditions (if names used are not the same, look for corresponding names)
      • DCLK on inlet

Momentum	Velocity Specification Method	Magnitude, Normal to Boundary
	Velocity Magnitude (m/s)	13.4112 This is equivalent to 30 mph. Use appropriate velocity depending on the case.

• DCLK on outlet

Momentum

Gauge Pressure (pascal)

0

• DCLK on all walls to confirm they are Stationary, No-Slip Walls with 0 Thermal properties.

• Reference Values

	Compute from	outlet
Reference Values	Density (kg/m3)	1.1839 This is for 25 C. Use case-specific values.
	Temperature (k)	298 This is for 25 C. Use case-specific values.